Koh Samui in December
In December, Koh Samui averages 28°C (82°F) during the day and 25°C (76°F) at night, with frequent rain — about 24 days of the month see precipitation (182 mm total).
ShoulderConditions are warm and beach-friendly. Expect daily rain or showers, often in heavy bursts.
December offers comfortable temperatures in Koh Samui, with some rain to plan around.
How December compares to the rest of the year in Koh Samui
December is one of the coolest months in Koh Samui (12th of 12) and moderately rainy compared to the rest of the year (9th of 12). Daytime temperature runs 2°C below the annual average (29°C). December runs roughly the same as November (28°C) and stays flat into January.
December sunrise & sunset in Koh Samui
Times shown for Koh Samui local time (Asia/Bangkok), calculated for the 15th of December. They shift by a few minutes day to day across the month.
Photography light in Koh Samui — December
Golden-hour and blue-hour windows for the 15th of December, in Koh Samui's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Koh Samui in December
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on December's tier (Shoulder) and Koh Samui's popularity.
Crowds & pricing — December in Koh Samui
Koh Samui is in a shoulder season month — fewer crowds, slightly lower prices, and a calmer atmosphere than peak weeks. Most major sights stay open with normal hours, though a handful of seasonal restaurants or boat trips may run reduced schedules. Many regulars consider these months the best time to visit because you trade a small amount of weather reliability for a much more pleasant on-the-ground experience.
Why this tier: Christmas / New Year travel surge
Sun & mosquito risk — December in Koh Samui
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Sea temperature in Koh Samui — December
Across the year Koh Samui's sea swings from 28.6°C (January) to 32.1°C (May) — December sits at 28.8°C.
Koh Samui in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 28°C / 82°F | 25°C / 76°F | 113 mm | 24 | — |
| February | 28°C / 83°F | 25°C / 77°F | 33 mm | 17 | — |
| March | 30°C / 86°F | 26°C / 78°F | 32 mm | 17 | — |
| April | 31°C / 87°F | 27°C / 80°F | 107 mm | 23 | — |
| May | 31°C / 87°F | 27°C / 80°F | 130 mm | 29 | — |
| June | 30°C / 86°F | 27°C / 80°F | 96 mm | 27 | — |
| July | 30°C / 86°F | 26°C / 79°F | 115 mm | 28 | — |
| August | 30°C / 86°F | 26°C / 79°F | 94 mm | 28 | — |
| September | 29°C / 84°F | 26°C / 78°F | 172 mm | 29 | — |
| October | 28°C / 83°F | 25°C / 77°F | 234 mm | 31 | — |
| November | 28°C / 82°F | 25°C / 77°F | 274 mm | 29 | — |
| December | 28°C / 82°F | 25°C / 76°F | 182 mm | 24 | — |
Other cities with similar December weather
🌍 See the full ranked list of climate twins for Koh Samui in December →
Frequently asked questions
How hot is Koh Samui in December?
In December, Koh Samui averages a high of 28°C (82°F) and a low of 25°C (76°F) — generally warm.
Does it rain a lot in Koh Samui in December?
December is quite rainy in Koh Samui, with about 24 rainy days on average.
Is December a good time to visit Koh Samui?
December is warm but on the rainy side. It suits travelers who are comfortable with warm weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Koh Samui in December?
Pack lightweight, breathable clothing, sunglasses and sunscreen, plus a compact umbrella or rain jacket. See the full December packing list for Koh Samui for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.